Polyurethane ball for games and sports

ABSTRACT

A polyurethane ball for games and sports includes a core portion made of relatively heavy and low-cost materials and in the shape of a regular spherical body, and an outer portion made of a polyurethane material and having a predetermined thickness to enclose the entire core portion. The ball is manufactured by way of centering a pre-molded core portion in a mold and filling the mold with the polyurethane material to produce an integral ball. The materials for the core portion include rubber or foamed rubber, plastics or foamed plastics, or recycled wood materials. A heavy-weight filler, such as powdered calcium carbonate, may be blended into the materials for the core portion, so as to effectively control an overall weight of the polyurethane ball.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a polyurethane ball for gamesand sports, and more particularly to a ball having a core portion madeof relatively weight and low-cost materials, and an outer portion madeof a polyurethane material and having a predetermined thickness toenclose the core portion. The ball is formed by centering the coreportion, which is separately molded first, in a mold and filling themold with a polyurethane material, so that the ball has desired weightand elasticity without increasing the amount of polyurethane materialthat is expensive.

[0002] Polyurethane (PU) balls are available in various sizes from assmall as a baseball to a ball as large as 8 inches in diameter, so as tomeet different demands in the markets and be used in different games andsports. There are times when a polyurethane ball preferably has anincreased weight. A conventional way to increase the weight of thepolyurethane ball is to lower the foaming power of the polyurethanematerial used to form the ball. However, this will relatively increasethe amount of polyurethane material in forming the ball, particularly inthe case of the 8-inch ball. Since the polyurethane material is three orfour times as expensive as other plastic materials, such as polyethylene(PE), polypropylene (PP), and polyvinyl chloride (PVC), increased amountof polyurethane material will largely increase the manufacturing cost ofthe polyurethane ball. This fact inevitably prevents theweight-increased polyurethane balls from being widely accepted in themarkets and brings troubles to the manufacturers in selling the same.

[0003] It is therefore desirable to develop a polyurethane ball thateliminates the above-mentioned drawbacks.

SUMMARY OF THE INVENTION

[0004] A primary object of the present invention is to provide apolyurethane ball that has a core portion made of relatively weight andlow-cost materials, and an outer portion made of a polyurethane materialand having a predetermined thickness to enclose the core portion. Theball is formed by means of centering a pre-molded core portion in a moldand filling the mold with a polyurethane material, so that the ball mayhave desired weight and elasticity without increasing the amount ofpolyurethane material that is expensive.

[0005] Another object of the present invention is to provide apolyurethane ball for games and sports having an integrally molded outerportion enclosing a core portion that is separately molded with low-costmaterials, such as rubber or foamed rubber, plastics or foamed plastics,or recycled wood materials. A heavy-weight filler, such as powderedcalcium carbonate, may be added into the materials for forming the coreportion, so as to effectively control the final molded weight of thepolyurethane ball.

[0006] A further object of the present invention is to provide apolyurethane ball for games and sports having a core portion enclosed ina layer of polyurethane material, on an outer surface of whichdifferently colored or patterned decorative areas or a plurality ofraised small dots are provided through molding to create good appearanceand hand feeling.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The structure and the technical means adopted by the presentinvention to achieve the above and other objects can be best understoodby referring to the following detailed description of the preferredembodiments and the accompanying drawings, wherein

[0008]FIG. 1 is a perspective view of a polyurethane ball for games andsports according to the present invention, wherein a part of the outerportion of the ball is cut away to show an internal structure thereof;

[0009]FIG. 2 is a perspective view of an embodiment of the presentinvention;

[0010]FIG. 3 is a perspective view of another embodiment of the presentinvention; and

[0011]FIG. 4 is a sectioned side view showing the forming of the presentinvention in a mold.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Please refer to FIG. 1. The present invention relates to apolyurethane ball 1 for games and sports. The ball 1 mainly includes acore portion 10 and an outer portion 20. The outer portion 20 is moldedfrom a polyurethane material, while the core portion 10 maybe made ofrubber or foamed rubber, various types of plastic materials or foamedplastic materials, or recycled wood materials, that all are low-costmaterials, to have a properly controlled net weight. An adequate amountof heavy-weight filler, such as powdered calcium carbonate (CaCO₃), maybe added and blended into the materials of the core portion 10 toeffectively control a final weight of the molded core portion 10, andaccordingly, of the whole polyurethane ball 1.

[0013] The core portion 10 is a separately molded regular sphericalbody, a diameter and a net weight of which are determined depending onactual usages or manufacturers' specifications. Taking a polyurethaneball 1 having a diameter of 8 inches (8″) as an example, there areusually two specifications available, namely, 5-pound (lb) and 2.5-pound(lb) balls. There are multiple combinations of diameter of core portion10 and thickness of outer portion 20 available for users. It is mostpreferable the outer portion 20 has a thickness as small as possible todecrease the amount of polyurethane material used to make the ball 1 andtherefore reduce the manufacturing cost thereof. The outer portion 20may have a thickness within the range from 5 mm to 20 mm or more.Generally, an outer portion 20 of 5 mm is thick enough to providedesired surface texture and sufficient elasticity.

[0014]FIG. 2 shows a first embodiment of the polyurethane ball 1 of thepresent invention. In this first embodiment, the ball 1 is formed on anouter surface of the outer portion 20 with differently colored orpatterned decorative areas 21. This can be achieved through mold design.And, FIG. 3 shows a second embodiment of the polyurethane ball 1 thathas a plurality of raised small dots 22 evenly distributed over an outersurface of the outer portion 20 to create changes in the appearance ofthe ball 1 as well as a different hand feeling. Such changes in theappearance of the polyurethane ball 1 enable the ball 1 to meetdifferent demands in the markets.

[0015] The polyurethane ball 1 is produced by way of molding. FIG. 4 isa sectioned side view of a mold 30 for forming the ball 1. The coreportion 10 in the form of a regular spherical body is separately moldedfirst and then disposed at a center of the mold 30. Thereafter, thepolyurethane material is filled into the mold 30, so that the coreportion 10 and the polyurethane material together form an integral unit.Since the core portion 10 is initially a separately molded sphericalbody, it basically has a middle parting line 11 formed thereon tofacilitate stripping of mold. When the molded core portion 10 isdisposed on a locating pin 31 in the mold 30, aligning of the middleparting line 11 on the core portion 10 with a mold joint 32 of the mold30 could ensure accurate centering of the core portion 10 in the mold 30and accordingly good quality of the molded polyurethane ball 1.

[0016] The present invention has been described with preferredembodiments thereof and it is understood that many changes andmodifications in the described embodiments can be carried out withoutdeparting from the scope and the spirit of the invention as defined bythe appended claims.

What is claimed is:
 1. A polyurethane ball for games and sports,comprising a core portion and an outer portion; said core portion beinga regular spherical body separately molded from relatively heavy andlow-cost materials; and said outer portion being made of a polyurethanematerial and having a predetermined thickness to enclose said coreportion therein by centering said core portion in a mold and fillingsaid mold with said polyurethane material to produce an integral unit ofsaid core portion and said outer portion.
 2. The polyurethane ball forgames and sports as claimed in claim 1, wherein said core portion ismade of rubber or foamed rubber material.
 3. The polyurethane ball forgames and sports as claimed in claim 1, wherein said core portion ismade of plastics or foamed plastic material.
 4. The polyurethane ballfor games and sports as claimed in claim 1, wherein said core portion ismade of recycled wood materials.
 5. The polyurethane ball for games andsports as claimed in claim 1, wherein said core portion includes aheavy-weight filler added and blended into materials for forming saidcore portion.
 6. The polyurethane ball for games and sports as claimedin claim 5, wherein said heavy-weight filler is powdered calciumcarbonate.
 7. The polyurethane ball for games and sports as claimed inclaim 1, wherein said outer portion has a thickness within the rangefrom 5 mm to 20 mm or more.